/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*                                        MESSAGE QUEUE MANAGEMENT
*
*                          (c) Copyright 1992-2006, Jean J. Labrosse, Weston, FL
*                                           All Rights Reserved
*
* File    : OS_Q.C
* By      : Jean J. Labrosse
* Version : V2.84
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include <ucos_ii.h>
#endif

#if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
/*
*********************************************************************************************************
*                                      ACCEPT MESSAGE FROM QUEUE
*
* Description: This function checks the queue to see if a message is available.  Unlike OSQPend(),
*              OSQAccept() does not suspend the calling task if a message is not available.
*
* Arguments  : pevent        is a pointer to the event control block
*
*              err           is a pointer to where an error message will be deposited.  Possible error
*                            messages are:
*
*                            OS_NO_ERR           The call was successful and your task received a
*                                                message.
*                            OS_ERR_EVENT_TYPE   You didn't pass a pointer to a queue
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer
*                            OS_Q_EMPTY          The queue did not contain any messages
*
* Returns    : != (void *)0  is the message in the queue if one is available.  The message is removed
*                            from the so the next time OSQAccept() is called, the queue will contain
*                            one less entry.
*              == (void *)0  if you received a NULL pointer message
*                            if the queue is empty or,
*                            if 'pevent' is a NULL pointer or,
*                            if you passed an invalid event type
*
* Note(s)    : As of V2.60, you can now pass NULL pointers through queues.  Because of this, the argument
*              'err' has been added to the API to tell you about the outcome of the call.
*********************************************************************************************************
*/

#if OS_Q_ACCEPT_EN > 0
void  *OSQAccept (OS_EVENT *pevent, INT8U *err)
{
        void      *msg;
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (err == (INT8U *)0)                       /* Validate 'err'                                     */
        {
                return ((void *)0);
        }

        if (pevent == (OS_EVENT *)0)                 /* Validate 'pevent'                                  */
        {
                *err = OS_ERR_PEVENT_NULL;
                return ((void *)0);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)  /* Validate event block type                          */
        {
                *err = OS_ERR_EVENT_TYPE;
                return ((void *)0);
        }

        OS_ENTER_CRITICAL();
        pq = (OS_Q *)pevent->OSEventPtr;             /* Point at queue control block                       */

        if (pq->OSQEntries > 0)                      /* See if any messages in the queue                   */
        {
                msg = *pq->OSQOut++;                     /* Yes, extract oldest message from the queue         */
                pq->OSQEntries--;                        /* Update the number of entries in the queue          */

                if (pq->OSQOut == pq->OSQEnd)            /* Wrap OUT pointer if we are at the end of the queue */
                {
                        pq->OSQOut = pq->OSQStart;
                }

                *err = OS_NO_ERR;
        }
        else
        {
                *err = OS_Q_EMPTY;
                msg  = (void *)0;                        /* Queue is empty                                     */
        }

        OS_EXIT_CRITICAL();
        return (msg);                                /* Return message received (or NULL)                  */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                        CREATE A MESSAGE QUEUE
*
* Description: This function creates a message queue if free event control blocks are available.
*
* Arguments  : start         is a pointer to the base address of the message queue storage area.  The
*                            storage area MUST be declared as an array of pointers to 'void' as follows
*
*                            void *MessageStorage[size]
*
*              size          is the number of elements in the storage area
*
* Returns    : != (OS_EVENT *)0  is a pointer to the event control clock (OS_EVENT) associated with the
*                                created queue
*              == (OS_EVENT *)0  if no event control blocks were available or an error was detected
*********************************************************************************************************
*/

OS_EVENT  *OSQCreate (void **start, INT16U size)
{
        OS_EVENT  *pevent;
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
        OS_CPU_SR  cpu_sr = 0;
#endif

        if (OSIntNesting > 0)                        /* See if called from ISR ...                         */
        {
                return ((OS_EVENT *)0);                  /* ... can't CREATE from an ISR                       */
        }

        OS_ENTER_CRITICAL();
        pevent = OSEventFreeList;                    /* Get next free event control block                  */

        if (OSEventFreeList != (OS_EVENT *)0)        /* See if pool of free ECB pool was empty             */
        {
                OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
        }

        OS_EXIT_CRITICAL();

        if (pevent != (OS_EVENT *)0)                 /* See if we have an event control block              */
        {
                OS_ENTER_CRITICAL();
                pq = OSQFreeList;                        /* Get a free queue control block                     */

                if (pq != (OS_Q *)0)                     /* Were we able to get a queue control block ?        */
                {
                        OSQFreeList            = OSQFreeList->OSQPtr; /* Yes, Adjust free list pointer to next free*/
                        OS_EXIT_CRITICAL();
                        pq->OSQStart           = start;               /*      Initialize the queue                 */
                        pq->OSQEnd             = &start[size];
                        pq->OSQIn              = start;
                        pq->OSQOut             = start;
                        pq->OSQSize            = size;
                        pq->OSQEntries         = 0;
                        pevent->OSEventType    = OS_EVENT_TYPE_Q;
                        pevent->OSEventCnt     = 0;
                        pevent->OSEventPtr     = pq;
#if OS_EVENT_NAME_SIZE > 1
                        pevent->OSEventName[0] = '?';                  /* Unknown name                             */
                        pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
                        OS_EventWaitListInit(pevent);                 /*      Initalize the wait list              */
                }
                else
                {
                        pevent->OSEventPtr = (void *)OSEventFreeList; /* No,  Return event control block on error  */
                        OSEventFreeList    = pevent;
                        OS_EXIT_CRITICAL();
                        pevent = (OS_EVENT *)0;
                }
        }

        return (pevent);
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                        DELETE A MESSAGE QUEUE
*
* Description: This function deletes a message queue and readies all tasks pending on the queue.
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired
*                            queue.
*
*              opt           determines delete options as follows:
*                            opt == OS_DEL_NO_PEND   Delete the queue ONLY if no task pending
*                            opt == OS_DEL_ALWAYS    Deletes the queue even if tasks are waiting.
*                                                    In this case, all the tasks pending will be readied.
*
*              err           is a pointer to an error code that can contain one of the following values:
*                            OS_NO_ERR               The call was successful and the queue was deleted
*                            OS_ERR_DEL_ISR          If you tried to delete the queue from an ISR
*                            OS_ERR_INVALID_OPT      An invalid option was specified
*                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the queue
*                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a queue
*                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer.
*
* Returns    : pevent        upon error
*              (OS_EVENT *)0 if the queue was successfully deleted.
*
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of
*                 the queue MUST check the return code of OSQPend().
*              2) OSQAccept() callers will not know that the intended queue has been deleted unless
*                 they check 'pevent' to see that it's a NULL pointer.
*              3) This call can potentially disable interrupts for a long time.  The interrupt disable
*                 time is directly proportional to the number of tasks waiting on the queue.
*              4) Because ALL tasks pending on the queue will be readied, you MUST be careful in
*                 applications where the queue is used for mutual exclusion because the resource(s)
*                 will no longer be guarded by the queue.
*              5) If the storage for the message queue was allocated dynamically (i.e. using a malloc()
*                 type call) then your application MUST release the memory storage by call the counterpart
*                 call of the dynamic allocation scheme used.  If the queue storage was created statically
*                 then, the storage can be reused.
*********************************************************************************************************
*/

#if OS_Q_DEL_EN > 0
OS_EVENT  *OSQDel (OS_EVENT *pevent, INT8U opt, INT8U *err)
{
        BOOLEAN    tasks_waiting;
        OS_EVENT  *pevent_return;
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (err == (INT8U *)0)                                 /* Validate 'err'                           */
        {
                return (pevent);
        }

        if (pevent == (OS_EVENT *)0)                           /* Validate 'pevent'                        */
        {
                *err = OS_ERR_PEVENT_NULL;
                return (pevent);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)            /* Validate event block type                */
        {
                *err = OS_ERR_EVENT_TYPE;
                return (pevent);
        }

        if (OSIntNesting > 0)                                  /* See if called from ISR ...               */
        {
                *err = OS_ERR_DEL_ISR;                             /* ... can't DELETE from an ISR             */
                return (pevent);
        }

        OS_ENTER_CRITICAL();

        if (pevent->OSEventGrp != 0)                           /* See if any tasks waiting on queue        */
        {
                tasks_waiting = OS_TRUE;                              /* Yes                                      */
        }
        else
        {
                tasks_waiting = OS_FALSE;                             /* No                                       */
        }

        switch (opt)
        {
                case OS_DEL_NO_PEND:                               /* Delete queue only if no task waiting     */
                        if (tasks_waiting == OS_FALSE)
                        {
#if OS_EVENT_NAME_SIZE > 1
                                pevent->OSEventName[0] = '?';             /* Unknown name                             */
                                pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
                                pq                     = (OS_Q *)pevent->OSEventPtr;  /* Return OS_Q to free list     */
                                pq->OSQPtr             = OSQFreeList;
                                OSQFreeList            = pq;
                                pevent->OSEventType    = OS_EVENT_TYPE_UNUSED;
                                pevent->OSEventPtr     = OSEventFreeList; /* Return Event Control Block to free list  */
                                pevent->OSEventCnt     = 0;
                                OSEventFreeList        = pevent;          /* Get next free event control block        */
                                OS_EXIT_CRITICAL();
                                *err                   = OS_NO_ERR;
                                pevent_return          = (OS_EVENT *)0;   /* Queue has been deleted                   */
                        }
                        else
                        {
                                OS_EXIT_CRITICAL();
                                *err                   = OS_ERR_TASK_WAITING;
                                pevent_return          = pevent;
                        }

                        break;

                case OS_DEL_ALWAYS:                                /* Always delete the queue                  */
                        while (pevent->OSEventGrp != 0)               /* Ready ALL tasks waiting for queue        */
                        {
                                (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_Q);
                        }

#if OS_EVENT_NAME_SIZE > 1
                        pevent->OSEventName[0] = '?';                 /* Unknown name                             */
                        pevent->OSEventName[1] = OS_ASCII_NUL;
#endif
                        pq                     = (OS_Q *)pevent->OSEventPtr;   /* Return OS_Q to free list        */
                        pq->OSQPtr             = OSQFreeList;
                        OSQFreeList            = pq;
                        pevent->OSEventType    = OS_EVENT_TYPE_UNUSED;
                        pevent->OSEventPtr     = OSEventFreeList;     /* Return Event Control Block to free list  */
                        pevent->OSEventCnt     = 0;
                        OSEventFreeList        = pevent;              /* Get next free event control block        */
                        OS_EXIT_CRITICAL();

                        if (tasks_waiting == OS_TRUE)                    /* Reschedule only if task(s) were waiting  */
                        {
                                OS_Sched();                               /* Find highest priority task ready to run  */
                        }

                        *err                   = OS_NO_ERR;
                        pevent_return          = (OS_EVENT *)0;       /* Queue has been deleted                   */
                        break;

                default:
                        OS_EXIT_CRITICAL();
                        *err                   = OS_ERR_INVALID_OPT;
                        pevent_return          = pevent;
                        break;
        }

        return (pevent_return);
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                             FLUSH QUEUE
*
* Description : This function is used to flush the contents of the message queue.
*
* Arguments   : none
*
* Returns     : OS_NO_ERR           upon success
*               OS_ERR_EVENT_TYPE   If you didn't pass a pointer to a queue
*               OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer
*
* WARNING     : You should use this function with great care because, when to flush the queue, you LOOSE
*               the references to what the queue entries are pointing to and thus, you could cause
*               'memory leaks'.  In other words, the data you are pointing to that's being referenced
*               by the queue entries should, most likely, need to be de-allocated (i.e. freed).
*********************************************************************************************************
*/

#if OS_Q_FLUSH_EN > 0
INT8U  OSQFlush (OS_EVENT *pevent)
{
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (pevent == (OS_EVENT *)0)                      /* Validate 'pevent'                             */
        {
                return (OS_ERR_PEVENT_NULL);
        }

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)       /* Validate event block type                     */
        {
                return (OS_ERR_EVENT_TYPE);
        }

#endif
        OS_ENTER_CRITICAL();
        pq             = (OS_Q *)pevent->OSEventPtr;      /* Point to queue storage structure              */
        pq->OSQIn      = pq->OSQStart;
        pq->OSQOut     = pq->OSQStart;
        pq->OSQEntries = 0;
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                     PEND ON A QUEUE FOR A MESSAGE
*
* Description: This function waits for a message to be sent to a queue
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue
*
*              timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will
*                            wait for a message to arrive at the queue up to the amount of time
*                            specified by this argument.  If you specify 0, however, your task will wait
*                            forever at the specified queue or, until a message arrives.
*
*              err           is a pointer to where an error message will be deposited.  Possible error
*                            messages are:
*
*                            OS_NO_ERR           The call was successful and your task received a
*                                                message.
*                            OS_TIMEOUT          A message was not received within the specified timeout
*                            OS_ERR_EVENT_TYPE   You didn't pass a pointer to a queue
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer
*                            OS_ERR_PEND_ISR     If you called this function from an ISR and the result
*                                                would lead to a suspension.
*                            OS_ERR_PEND_LOCKED  If you called this function with the scheduler is locked
*
* Returns    : != (void *)0  is a pointer to the message received
*              == (void *)0  if you received a NULL pointer message or,
*                            if no message was received or,
*                            if 'pevent' is a NULL pointer or,
*                            if you didn't pass a pointer to a queue.
*
* Note(s)    : As of V2.60, this function allows you to receive NULL pointer messages.
*********************************************************************************************************
*/

void  *OSQPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
        void      *msg;
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (err == (INT8U *)0)                       /* Validate 'err'                                     */
        {
                return ((void *)0);
        }

        if (pevent == (OS_EVENT *)0)                 /* Validate 'pevent'                                  */
        {
                *err = OS_ERR_PEVENT_NULL;
                return ((void *)0);
        }

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)  /* Validate event block type                          */
        {
                *err = OS_ERR_EVENT_TYPE;
                return ((void *)0);
        }

#endif

        if (OSIntNesting > 0)                        /* See if called from ISR ...                         */
        {
                *err = OS_ERR_PEND_ISR;                  /* ... can't PEND from an ISR                         */
                return ((void *)0);
        }

        if (OSLockNesting > 0)                       /* See if called with scheduler locked ...            */
        {
                *err = OS_ERR_PEND_LOCKED;               /* ... can't PEND when locked                         */
                return ((void *)0);
        }

        OS_ENTER_CRITICAL();
        pq = (OS_Q *)pevent->OSEventPtr;             /* Point at queue control block                       */

        if (pq->OSQEntries > 0)                      /* See if any messages in the queue                   */
        {
                msg = *pq->OSQOut++;                     /* Yes, extract oldest message from the queue         */
                pq->OSQEntries--;                        /* Update the number of entries in the queue          */

                if (pq->OSQOut == pq->OSQEnd)            /* Wrap OUT pointer if we are at the end of the queue */
                {
                        pq->OSQOut = pq->OSQStart;
                }

                OS_EXIT_CRITICAL();
                *err = OS_NO_ERR;
                return (msg);                            /* Return message received                            */
        }

        OSTCBCur->OSTCBStat   |= OS_STAT_Q;          /* Task will have to pend for a message to be posted  */
        OSTCBCur->OSTCBPendTO  = OS_FALSE;
        OSTCBCur->OSTCBDly     = timeout;            /* Load timeout into TCB                              */
        OS_EventTaskWait(pevent);                    /* Suspend task until event or timeout occurs         */
        OS_EXIT_CRITICAL();
        OS_Sched();                                  /* Find next highest priority task ready to run       */
        OS_ENTER_CRITICAL();

        if (OSTCBCur->OSTCBPendTO == OS_TRUE)           /* Was task readied because of a timeout?             */
        {
                OS_EventTO(pevent);                      /* Yes                                                */
                OS_EXIT_CRITICAL();
                *err = OS_TIMEOUT;                       /*     Indicate a timeout occured                     */
                return ((void *)0);                      /*     No message received                            */
        }

        msg                     = OSTCBCur->OSTCBMsg;/* No, Extract message from TCB (Put there by QPost)  */
        OSTCBCur->OSTCBMsg      = (void *)0;
        OSTCBCur->OSTCBStat     = OS_STAT_RDY;
        OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;     /*     No longer waiting for event                    */
        OS_EXIT_CRITICAL();
        *err                    = OS_NO_ERR;
        return (msg);                                /*     Return message received                        */
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                        POST MESSAGE TO A QUEUE
*
* Description: This function sends a message to a queue
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue
*
*              msg           is a pointer to the message to send.
*
* Returns    : OS_NO_ERR             The call was successful and the message was sent
*              OS_Q_FULL             If the queue cannot accept any more messages because it is full.
*              OS_ERR_EVENT_TYPE     If you didn't pass a pointer to a queue.
*              OS_ERR_PEVENT_NULL    If 'pevent' is a NULL pointer
*
* Note(s)    : As of V2.60, this function allows you to send NULL pointer messages.
*********************************************************************************************************
*/

#if OS_Q_POST_EN > 0
INT8U  OSQPost (OS_EVENT *pevent, void *msg)
{
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                            /* Allocate storage for CPU status register     */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (pevent == (OS_EVENT *)0)                       /* Validate 'pevent'                            */
        {
                return (OS_ERR_PEVENT_NULL);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)        /* Validate event block type                    */
        {
                return (OS_ERR_EVENT_TYPE);
        }

        OS_ENTER_CRITICAL();

        if (pevent->OSEventGrp != 0)                       /* See if any task pending on queue             */
        {
                (void)OS_EventTaskRdy(pevent, msg, OS_STAT_Q); /* Ready highest priority task waiting on event */
                OS_EXIT_CRITICAL();
                OS_Sched();                                    /* Find highest priority task ready to run      */
                return (OS_NO_ERR);
        }

        pq = (OS_Q *)pevent->OSEventPtr;                   /* Point to queue control block                 */

        if (pq->OSQEntries >= pq->OSQSize)                 /* Make sure queue is not full                  */
        {
                OS_EXIT_CRITICAL();
                return (OS_Q_FULL);
        }

        *pq->OSQIn++ = msg;                                /* Insert message into queue                    */
        pq->OSQEntries++;                                  /* Update the nbr of entries in the queue       */

        if (pq->OSQIn == pq->OSQEnd)                       /* Wrap IN ptr if we are at end of queue        */
        {
                pq->OSQIn = pq->OSQStart;
        }

        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                   POST MESSAGE TO THE FRONT OF A QUEUE
*
* Description: This function sends a message to a queue but unlike OSQPost(), the message is posted at
*              the front instead of the end of the queue.  Using OSQPostFront() allows you to send
*              'priority' messages.
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue
*
*              msg           is a pointer to the message to send.
*
* Returns    : OS_NO_ERR             The call was successful and the message was sent
*              OS_Q_FULL             If the queue cannot accept any more messages because it is full.
*              OS_ERR_EVENT_TYPE     If you didn't pass a pointer to a queue.
*              OS_ERR_PEVENT_NULL    If 'pevent' is a NULL pointer
*
* Note(s)    : As of V2.60, this function allows you to send NULL pointer messages.
*********************************************************************************************************
*/

#if OS_Q_POST_FRONT_EN > 0
INT8U  OSQPostFront (OS_EVENT *pevent, void *msg)
{
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (pevent == (OS_EVENT *)0)                      /* Validate 'pevent'                             */
        {
                return (OS_ERR_PEVENT_NULL);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)       /* Validate event block type                     */
        {
                return (OS_ERR_EVENT_TYPE);
        }

        OS_ENTER_CRITICAL();

        if (pevent->OSEventGrp != 0)                      /* See if any task pending on queue              */
        {
                (void)OS_EventTaskRdy(pevent, msg, OS_STAT_Q);/* Ready highest priority task waiting on event  */
                OS_EXIT_CRITICAL();
                OS_Sched();                                   /* Find highest priority task ready to run       */
                return (OS_NO_ERR);
        }

        pq = (OS_Q *)pevent->OSEventPtr;                  /* Point to queue control block                  */

        if (pq->OSQEntries >= pq->OSQSize)                /* Make sure queue is not full                   */
        {
                OS_EXIT_CRITICAL();
                return (OS_Q_FULL);
        }

        if (pq->OSQOut == pq->OSQStart)                   /* Wrap OUT ptr if we are at the 1st queue entry */
        {
                pq->OSQOut = pq->OSQEnd;
        }

        pq->OSQOut--;
        *pq->OSQOut = msg;                                /* Insert message into queue                     */
        pq->OSQEntries++;                                 /* Update the nbr of entries in the queue        */
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                        POST MESSAGE TO A QUEUE
*
* Description: This function sends a message to a queue.  This call has been added to reduce code size
*              since it can replace both OSQPost() and OSQPostFront().  Also, this function adds the
*              capability to broadcast a message to ALL tasks waiting on the message queue.
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue
*
*              msg           is a pointer to the message to send.
*
*              opt           determines the type of POST performed:
*                            OS_POST_OPT_NONE         POST to a single waiting task
*                                                     (Identical to OSQPost())
*                            OS_POST_OPT_BROADCAST    POST to ALL tasks that are waiting on the queue
*                            OS_POST_OPT_FRONT        POST as LIFO (Simulates OSQPostFront())
*
*                            Below is a list of ALL the possible combination of these flags:
*
*                                 1) OS_POST_OPT_NONE
*                                    identical to OSQPost()
*
*                                 2) OS_POST_OPT_FRONT
*                                    identical to OSQPostFront()
*
*                                 3) OS_POST_OPT_BROADCAST
*                                    identical to OSQPost() but will broadcast 'msg' to ALL waiting tasks
*
*                                 4) OS_POST_OPT_FRONT + OS_POST_OPT_BROADCAST  is identical to
*                                    OSQPostFront() except that will broadcast 'msg' to ALL waiting tasks
*
* Returns    : OS_NO_ERR             The call was successful and the message was sent
*              OS_Q_FULL             If the queue cannot accept any more messages because it is full.
*              OS_ERR_EVENT_TYPE     If you didn't pass a pointer to a queue.
*              OS_ERR_PEVENT_NULL    If 'pevent' is a NULL pointer
*
* Warning    : Interrupts can be disabled for a long time if you do a 'broadcast'.  In fact, the
*              interrupt disable time is proportional to the number of tasks waiting on the queue.
*********************************************************************************************************
*/

#if OS_Q_POST_OPT_EN > 0
INT8U  OSQPostOpt (OS_EVENT *pevent, void *msg, INT8U opt)
{
        OS_Q      *pq;
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (pevent == (OS_EVENT *)0)                      /* Validate 'pevent'                             */
        {
                return (OS_ERR_PEVENT_NULL);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)       /* Validate event block type                     */
        {
                return (OS_ERR_EVENT_TYPE);
        }

        OS_ENTER_CRITICAL();

        if (pevent->OSEventGrp != 0x00)                   /* See if any task pending on queue              */
        {
                if ((opt & OS_POST_OPT_BROADCAST) != 0x00)    /* Do we need to post msg to ALL waiting tasks ? */
                {
                        while (pevent->OSEventGrp != 0)           /* Yes, Post to ALL tasks waiting on queue       */
                        {
                                (void)OS_EventTaskRdy(pevent, msg, OS_STAT_Q);
                        }
                }
                else
                {
                        (void)OS_EventTaskRdy(pevent, msg, OS_STAT_Q);  /* No,  Post to HPT waiting on queue       */
                }

                OS_EXIT_CRITICAL();

                if ((opt & OS_POST_OPT_NO_SCHED) == 0)
                {
                        OS_Sched();                                     /* Find highest priority task ready to run */
                }

                return (OS_NO_ERR);
        }

        pq = (OS_Q *)pevent->OSEventPtr;                  /* Point to queue control block                  */

        if (pq->OSQEntries >= pq->OSQSize)                /* Make sure queue is not full                   */
        {
                OS_EXIT_CRITICAL();
                return (OS_Q_FULL);
        }

        if ((opt & OS_POST_OPT_FRONT) != 0x00)            /* Do we post to the FRONT of the queue?         */
        {
                if (pq->OSQOut == pq->OSQStart)               /* Yes, Post as LIFO, Wrap OUT pointer if we ... */
                {
                        pq->OSQOut = pq->OSQEnd;                  /*      ... are at the 1st queue entry           */
                }

                pq->OSQOut--;
                *pq->OSQOut = msg;                            /*      Insert message into queue                */
        }
        else                                              /* No,  Post as FIFO                             */
        {
                *pq->OSQIn++ = msg;                           /*      Insert message into queue                */

                if (pq->OSQIn == pq->OSQEnd)                  /*      Wrap IN ptr if we are at end of queue    */
                {
                        pq->OSQIn = pq->OSQStart;
                }
        }

        pq->OSQEntries++;                                 /* Update the nbr of entries in the queue        */
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                        QUERY A MESSAGE QUEUE
*
* Description: This function obtains information about a message queue.
*
* Arguments  : pevent        is a pointer to the event control block associated with the desired queue
*
*              p_q_data      is a pointer to a structure that will contain information about the message
*                            queue.
*
* Returns    : OS_NO_ERR           The call was successful and the message was sent
*              OS_ERR_EVENT_TYPE   If you are attempting to obtain data from a non queue.
*              OS_ERR_PEVENT_NULL  If 'pevent'   is a NULL pointer
*              OS_ERR_PDATA_NULL   If 'p_q_data' is a NULL pointer
*********************************************************************************************************
*/

#if OS_Q_QUERY_EN > 0
INT8U  OSQQuery (OS_EVENT *pevent, OS_Q_DATA *p_q_data)
{
        OS_Q      *pq;
        INT8U      i;
#if OS_LOWEST_PRIO <= 63
        INT8U     *psrc;
        INT8U     *pdest;
#else
        INT16U    *psrc;
        INT16U    *pdest;
#endif
#if OS_CRITICAL_METHOD == 3                            /* Allocate storage for CPU status register     */
        OS_CPU_SR  cpu_sr = 0;
#endif
#if OS_ARG_CHK_EN > 0

        if (pevent == (OS_EVENT *)0)                       /* Validate 'pevent'                            */
        {
                return (OS_ERR_PEVENT_NULL);
        }

        if (p_q_data == (OS_Q_DATA *)0)                    /* Validate 'p_q_data'                          */
        {
                return (OS_ERR_PDATA_NULL);
        }

#endif

        if (pevent->OSEventType != OS_EVENT_TYPE_Q)        /* Validate event block type                    */
        {
                return (OS_ERR_EVENT_TYPE);
        }

        OS_ENTER_CRITICAL();
        p_q_data->OSEventGrp = pevent->OSEventGrp;         /* Copy message queue wait list                 */
        psrc                 = &pevent->OSEventTbl[0];
        pdest                = &p_q_data->OSEventTbl[0];

        for (i = 0; i < OS_EVENT_TBL_SIZE; i++)
        {
                *pdest++ = *psrc++;
        }

        pq = (OS_Q *)pevent->OSEventPtr;

        if (pq->OSQEntries > 0)
        {
                p_q_data->OSMsg = *pq->OSQOut;                 /* Get next message to return if available      */
        }
        else
        {
                p_q_data->OSMsg = (void *)0;
        }

        p_q_data->OSNMsgs = pq->OSQEntries;
        p_q_data->OSQSize = pq->OSQSize;
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
}
#endif                                                 /* OS_Q_QUERY_EN                                */

/*$PAGE*/
/*
*********************************************************************************************************
*                                      QUEUE MODULE INITIALIZATION
*
* Description : This function is called by uC/OS-II to initialize the message queue module.  Your
*               application MUST NOT call this function.
*
* Arguments   :  none
*
* Returns     : none
*
* Note(s)    : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

void  OS_QInit (void)
{
#if OS_MAX_QS == 1
        OSQFreeList         = &OSQTbl[0];                /* Only ONE queue!                                */
        OSQFreeList->OSQPtr = (OS_Q *)0;
#endif
#if OS_MAX_QS >= 2
        INT16U  i;
        OS_Q   *pq1;
        OS_Q   *pq2;
        OS_MemClr((INT8U *)&OSQTbl[0], sizeof(OSQTbl));  /* Clear the queue table                          */
        pq1 = &OSQTbl[0];
        pq2 = &OSQTbl[1];

        for (i = 0; i < (OS_MAX_QS - 1); i++)            /* Init. list of free QUEUE control blocks        */
        {
                pq1->OSQPtr = pq2;
                pq1++;
                pq2++;
        }

        pq1->OSQPtr = (OS_Q *)0;
        OSQFreeList = &OSQTbl[0];
#endif
}
#endif                                               /* OS_Q_EN                                        */
